Endoscopic surgical instruments are often preferred over traditional open surgical devices since a smaller incision, or incisions, associated with endoscopic surgical techniques tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a range of endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, radiofrequency (RF), laser, etc.).
In order to provide for better maneuverability and positioning of the end effector, many surgical devices enable articulation of the end effector as well as rotation of the shaft having the end effector at a distal end thereof. Articulation and rotation of the end effector can enable the surgeon to reach tissue that may otherwise be inaccessible. While in an articulated state, a load on the end effector creates a moment arm that can cause undesired rotation of the end effector.
Accordingly, there remains a need for increasing rotational torque during end effector articulation.